AWS Migration: Clark Construction Moved to AWS in a Week

  • Migration

The company went through AWS migration within a week — without anyone noticing except for IT

Aiming to eliminate the time that its IT staff spent maintaining on-site infrastructure, Clark Construction wanted to migrate its applications and data to the cloud. Using CloudEndure Migration, the company moved everything to AWS without a hitch. The migration lasted less than a week and went so smoothly that the employees outside of the IT department never knew the company’s servers had migrated.


With headquarters in Bethesda, Maryland, and 10 other regional offices around the U.S., Clark Construction is one of the largest privately-held general contractors in the country, with more than $4 billion in annual revenue. For more than a century, the company has completed intricate interior renovations and some of the most complex civil operations in the U.S. Clark Construction takes pride in providing world-class service to its clients and in its ability to handle projects of all sizes and levels of complexity.

The Challenge

Clark Construction set a goal to shift the applications and data from its 50 servers running in its data center to AWS by the end of the year. With limited staff, the company’s IT department wanted to spend more time on business operations and less time operating a data center and hardware facilities. Bob Gelety, the Director of Network Engineering at Clark Construction, and his staff chose AWS because of its reputation, but immediately realized the native migration tools AWS had provided to migrate the data and applications running on VMware architecture would not meet their time constraints.

After three migration tests with AWS native tools, it was obvious they needed a different solution. Clark Construction had a small window in which to migrate: downtime was limited to an 8-hour period — once every other month. Using AWS native tools, it would have taken days of downtime for Gelety and his two network administrators to migrate a terabyte of file-sharing applications and data into AWS, a luxury they didn’t have. Gelety was also faced with another hurdle: having six Oracle-based financial legacy workloads, which their vendor claimed could not be migrated to the cloud without being rebuilt.

The Solution

AWS recommended CloudEndure to Gelety’s team. Clark Construction wanted its migration to be handled by a proven enterprise-grade solution that could be deployed quickly, affordably, and without system disruption. Within a few hours of testing, Gelety and his staff had successfully migrated a couple of servers and immediately recognized that they could migrate all of their servers without complication or the limitations experienced with the cloud provider’s native tools — and with the speed that was needed to accommodate the 8-hour downtime window.

Preparation was important. Gelety and his team had methodically planned the migration project and wanted to ensure that every bit of data could be replicated before going live in AWS. CloudEndure’s support staff worked closely with Clark Construction’s IT staff, constantly checking the data’s continuous replication status before the planned cutover.


CloudEndure successfully replicated Clark Construction’s 26 applications. This process included the initial synchronization of existing server data and the continuous replication of any newly-written server data in real time. It was completed within several days.

At this point, Gelety and his team were able to test the most up-to-date state of their servers on AWS at a moment’s notice, as many times as needed, and without any disruption to their source applications. This ensured that when the golden 8-hour cutover window arrived, they knew exactly what to do, and could complete the cutover in minutes. When the time came, Gelety and his team simply spun up the most up-to-date state of their servers in AWS, and shut off their in-house servers.

The cutover period lasted minutes, and Gelety and his team knew it went smoothly as none of the 3,000 users working off of Clark Construction’s IT infrastructure noticed that the servers had moved, overnight, to AWS. In addition, CloudEndure’s ability to successfully migrate the six legacy financial applications to AWS without a hiccup — something the vendor had said couldn’t be done — was icing on the cake.

“I wanted to be able to say, ‘At midnight on Friday night…I want to be able to turn on these servers on Amazon and turn them off in our old environment,” Gelety said of CloudEndure Migration. CloudEndure enabled Gelety and his staff to migrate to AWS without fanfare. “We treat no news as good news,” he added.


With the migration successful and Clark Construction’s business continuity objectives reached, Gelety now plans to further leverage CloudEndure’s technology by using CloudEndure Disaster Recovery to maintain business continuity across multiple cloud providers and avoid being locked into one vendor.

More Case Studies